666117549 has 12 divisors (see below), whose sum is σ = 988174876. Its totient is φ = 432076032.

The previous prime is 666117503. The next prime is 666117589. The reversal of 666117549 is 945711666.

It can be written as a sum of positive squares in 2 ways, for example, as 534441924 + 131675625 = 23118^2 + 11475^2 .

It is not a de Polignac number, because 666117549 - 2⁸ = 666117293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (666117589) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 999844 + ... + 1000509.

Almost surely, 2^666117549 is an apocalyptic number.

It is an amenable number.

666117549 is a deficient number, since it is larger than the sum of its proper divisors (322057327).

666117549 is a wasteful number, since it uses less digits than its factorization.

666117549 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2000396 (or 2000393 counting only the distinct ones).

The product of its digits is 272160, while the sum is 45.

The square root of 666117549 is about 25809.2531662580. The cubic root of 666117549 is about 873.3405496202.

It can be divided in two parts, 666117 and 549, that added together give a palindrome (666666).

The spelling of 666117549 in words is "six hundred sixty-six million, one hundred seventeen thousand, five hundred forty-nine".